Electro-thermally driven biaxial bending artificial muscle based on oriented graphite nanoplate nanocomposite/polyimide complex structure

•The GNP/PI bi-layer films are fabricated by a simple and cost-effective approach which have light weight and large deformation.•Driven by the voltage of 10 V, the artificial muscle is able to reversibly reach a shrinkage rate of 11% and a maximum lifting height of 2.5 cm with the object weight of 5.0 g.•Based on the GN/PI bi-layers, a walking robot has also been designed to achieve a large displacement under the voltage of about 20.0 V.